Asda made the move despite saying it would not be taking part in Black Friday this year.

The discount ends on Monday.

The discounts will have added impact following the freeze on fuel duty announced in the Autumn Statement on Wednesday.

However Edmund King, AA president, warned that a cut in fuel prices beyond Black Friday is what is really needed to help UK drivers.

He said: "Apart from marketing gimmicks, pump prices haven't been below £1 per litre for five and a half years.

"Some drivers may wonder why petrol isn't one pound per litre across the board with oil trading at under 50 US dollars per barrel."

Asda president and CEO, Andy Clarke, said: "The Chancellor's freeze on fuel duty is what our customers were hoping for. We'd urge the Chancellor to continue with a freeze on fuel duty in the March Budget to help maintain discretionary income levels for families."

RAC spokesman Simon Williams said: "Due to the latest dip in the crude oil price we had predicted that the most price-competitive fuel retailers would soon be selling petrol for £1 so it is great to see that landmark price is now available across the country at the most expensive time of year.

"Even though this promotion only lasts for three days it will help to bring prices down at forecourts nationwide.

"While we are some way from seeing the average petrol price reach £1, prices at more and more retailers should be getting ever closer to that figure."